How should the receptor be oriented relative to the object's long axis?

• A. Parallel to the long axis of the object.
• B. Perpendicular to the long axis.
• C. At a 45-degree angle to the long axis.
• D. Parallel to the short axis of the object.

Answer: (A)

Aligning the receptor parallel to the object's long axis maximizes contact along the length of the object, giving the greatest surface area for interaction and more stable, uniform engagement. When the receptor sits this way, it can interact along a longer surface, improving sensitivity and consistency of response. Perpendicular orientation would limit contact to a short patch, reducing binding opportunities and signal reliability. A 45-degree angle offers intermediate contact that’s uneven along the length, and parallel to the short axis would engage a much shorter dimension. So the best arrangement is parallel to the long axis.